CPC · California Plumbing Code
What water heaters and appliance standards apply?
For homeowners: The CPC requires water heaters to meet the specific listed standards shown in Table 501.1(1) and to be installed per the manufacturer’s instructions; whether a heater is electric, gas (and whether its input is above or below 75,000 Btu/h), oil or solid‑fuel determines which standard applies—see **§ 501.1** and **Table 501.1(1)** for the authoritative list.
Last reviewed: July 6, 2026
What the code requires — 2-4 sentences
The California Plumbing Code requires that water heaters be of an accepted, listed appliance standard and installed per the manufacturer’s instructions. The chapter lists the accepted appliance standards and identifies the minimum storage capacity method; see § 501.1 and Table 501.1(1) for the list of standards and installation direction. Unlisted water heaters are permitted only as provided elsewhere in the code (referenced in § 501.1).
The single most important rule: water heaters must comply with the accepted appliance standards in Table 501.1(1) and be installed per the manufacturer’s instructions, with unlisted appliances only allowed where the code expressly permits. § 501.1
Requirements in detail
Scope and controlling rule
- The chapter governs the construction, location, and installation of fuel-burning and other types of water heaters that heat potable water, as well as their chimneys, vents and connectors — see § 501.1.
- The code requires use of the accepted appliance standards listed in Table 501.1(1). Listed appliances must be installed per the manufacturer’s installation instructions. § 501.1 and Table 501.1(1).
Accepted appliance standards — quick reference table
The table below extracts the decision‑relevant rows from Table 501.1(1) (use this to match a heater type to its required standard). Always confirm the manufacturer's listing matches the standard cited here. Table 501.1(1) — § 501.1.
| Water heater type (decision dimension) | Required standard | Code reference |
|---|---|---|
| Electric, household storage | UL 174 | Table 501.1(1), § 501.1 |
| Electric, commercial storage / booster | UL 1453 | Table 501.1(1), § 501.1 |
| Electric, instantaneous | UL 499 | Table 501.1(1), § 501.1 |
| Oil-fired storage tank | UL 732 | Table 501.1(1), § 501.1 |
| Gas‑fired storage, input ≤ 75,000 Btu/h | CSA/ANSI Z21.10.1 / CSA 4.1 | Table 501.1(1), § 501.1 |
| Gas‑fired storage or instantaneous, input > 75,000 Btu/h | CSA/ANSI Z21.10.3 / CSA 4.3 | Table 501.1(1), § 501.1 |
| Solid fuel‑fired | UL 2523 | Table 501.1(1), § 501.1 |
Notes:
- The 75,000 Btu/h threshold is explicit in Table 501.1(1) and determines which gas standard applies; the table also provides the SI conversion note: 1000 Btu/h = 0.293 kW. § 501.1.
- The code also states that dual‑purpose water heaters must comply with the code and manufacturer’s instructions (see § 501.1).
Listed vs. unlisted appliances; installation
- Listed appliances: If the appliance is listed to a standard in Table 501.1(1), install it according to the listing and the manufacturer’s installation instructions; final installation must be approved by the Authority Having Jurisdiction. § 501.1.
- Unlisted appliances: The code permits unlisted water heaters only in accordance with Section 504.3.2 (the provision is referenced in § 501.1). If you need to use an unlisted unit, follow the procedures and requirements set out in that section. § 501.1.
Other system-level and safety requirements (where appliance standard is not the only criterion)
- The code cross‑references energy and system requirements: § 501.2 references California Energy Code requirements for service water heating systems.
- For non‑gas fuels and special appliances, see Chapter provisions such as § 505.1 (appliances deriving heat from fuels other than gas), § 505.3 (oil‑fired water heaters — NFPA 31), and § 505.4 (indirect‑fired water heaters and ASME/other standards). These sections require compliance with the standards referenced in Table 501.1(1) or other applicable codes.
Exceptions & special cases
- Unlisted water heaters: permitted only per Section 504.3.2 (referenced by § 501.1). If the jurisdiction expects a listing and the appliance is unlisted, get approval under the referenced section. § 501.1.
- Oil-fired water heaters must be installed in accordance with NFPA 31 (see § 505.3).
- Indirect‑fired water heaters must meet ASME Boiler & Pressure Vessel Code sections or one of the standards in Table 501.1(1) and must bear the required ASME or testing‑agency label (see § 505.4).
- The energy code may add mandatory requirements for service water heating systems (see § 501.2 for CEC cross‑references).
If you require the exact permissive language or conditions in Section 504.3.2 or the numeric minimum storage capacities in Table 501.1(2), those specific items were not included in the retrieved excerpts; consult the full CPC text for those sections or ask me to fetch them.
Common mistakes
- Matching the wrong standard to the appliance type or input rating (example: using the ≤75,000 Btu/h gas standard for an appliance rated above that threshold). Always check Table 501.1(1) and the appliance input. § 501.1.
- Installing a listed appliance contrary to the manufacturer’s installation instructions — the code requires following the manufacturer’s instructions and listing terms. § 501.1.
- Assuming any unlisted unit is allowable without following the code’s procedure — unlisted units are allowed only per Section 504.3.2 (referenced in § 501.1).
- Overlooking other applicable sections (combustion air, venting, safety devices) — see § 505.1, § 504.4–504.7, and the venting chapters for those requirements.
Worked example
Scenario: A contractor is specifying a gas‑fired storage water heater with an input rating of 85,000 Btu/h.
- Determine applicable standard:
- Because 85,000 Btu/h > 75,000 Btu/h, the appliance falls into the “Above 75,000 Btu/h” category in Table 501.1(1); the required standard is CSA/ANSI Z21.10.3 / CSA 4.3. Table 501.1(1), § 501.1.
- Verify listing:
- Confirm the selected model is listed to CSA/ANSI Z21.10.3 / CSA 4.3 by reviewing the manufacturer’s label and product documentation.
- Installation:
- Install per the manufacturer’s instructions. The final installation must be approved by the Authority Having Jurisdiction, per § 501.1.
- Cross-check safety and venting:
- Follow venting, combustion air, relief device, and overtemperature/overpressure device requirements in the applicable code sections (see § 505.1, § 504.4–504.7 for related requirements).
- Convert to SI (if needed):
- The table notes 1000 Btu/h = 0.293 kW; therefore 85,000 Btu/h ≈ 24.9 kW (85 × 0.293). Table 501.1(1) note in § 501.1.
Related provisions
- § 501.1 — Applicability; list of accepted appliance standards and installation direction (controlling).
- Table 501.1(1) — List of water heater types and referenced standards (controlling).
- § 501.2 — California Energy Code cross‑references for water heating systems.
- § 504.3.2 — (Referenced by § 501.1) Procedure/conditions for permitting unlisted water heaters — consult full text.
- § 504.4 – § 504.7 — Pressure‑limiting, temperature‑limiting, and relief device requirements for water heater installations.
- § 505.1 — Requirements for water heaters deriving heat from fuels other than gas.
- § 505.3 — Oil‑fired water heater installation reference to NFPA 31.
- § 505.4 — Indirect‑fired water heaters (ASME or listed standard compliance).
Code references
Grounded in the retrieved California Plumbing Code — click a citation to read the verbatim passage:
CPC § 507.2 High relevance — show source text
2_
507.2|||X|X|X|||X|||||||||||||||||This state agency does not adopt sections identified with the following symbol: The Office of the State Fire Marshal’s adoption of this chapter or individual sections is applicable to structures regulated by other state agencies pursuant to Section 1.11.0.
2025 CALIFORNIA PLUMBING CODE 81
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CHAPTER 5
WATER HEATERS
501.0 General.
501.1 Applicability. The regulations of this chapter shall govern the construction, location, and installation of fuel-burning and other types of water heaters heating potable water, together with chimneys, vents, and their connectors. The minimum capacity for storage water heaters shall be in accordance with the first-hour rating listed in Table 501.1(2). A list of accepted water heater appliance standards is referenced in Table 501.1(1). Listed appliances shall be installed in accordance with the manufacturer’s installation instructions. Unlisted water heaters shall be permitted in accordance with Section 504.3.2.
Water heaters shall be installed in accordance with the
manufacturer’s installation instructions. The final installation shall be approved by the Authority Having Jurisdiction.
TABLE 501.1(1)
WATER HEATERS
TYPE* STANDARD
Electric, Household StorageUL 174
Oil-Fired Storage TankUL 732
Gas-Fired, 75 000 Btu/h or less,
StorageCSA/ANSI Z21.10.1/CSA 4.1
Gas-Fired, Above 75 000 Btu/h,
Storage and InstantaneousCSA/ANSI Z21.10.3/CSA 4.3
Electric, Commercial StorageUL 1453 Solid Fuel-Fired UL 2523
Electric InstantaneousUL 499 For SI units: 1000 British thermal units per hour = 0.293 kW
- Dual purpose water heaters shall be installed in accordance with this code and the manufacturer’s installation instructions.
501.2 California Energy Code Water Heating System Requirements. [CEC] See California Energy Code Section 110.3 for additional mandatory requirements for all service water heating systems, and 150.0(n) for additional mandatory requirements for residential service water heating systems.
502.0 Permits.
502.1 General. It shall be unlawful for a person to install, remove, or replace or cause to be installed, removed, or replaced a water heater without first obtaining a permit from the Authority Having Jurisdiction to do so.
TABLE 501.1(1)
WATER HEATERS
For SI units: 1000 British thermal units per hour = 0.293 kW
- Dual purpose water heaters shall be installed in accordance with this code and the manufacturer’s installation instructions.
503.0 Inspection.
CPC § 505.0 High relevance — show source text
505.0 Oil-Burning and Other Water Heaters. 505.1 Water Heaters. Water heaters deriving heat from fuels or types of energy other than gas shall comply with the standards referenced in Table 501.1(1), Section 505.3, or Section 505.4. Vents or chimneys for such appliances shall be of approved types. An adequate supply of air for combustion and for adequate ventilation of heater rooms or compartments shall be provided. Each such appliance shall be installed in a
location approved by the Authority Having Jurisdiction and local and state fire-prevention agencies. 505.2 Safety Devices. Storage-type water heaters and hot water boilers deriving heat from fuels or types of energy other than gas, shall be provided with, in addition to the primary temperature controls, an over-temperature safety protection device that complies with and is installed in accordance with nationally recognized applicable standards for such devices and a combination temperature and pressure-relief valve.
505.3 Oil-Fired Water Heaters. Oil-fired water heaters
shall be installed in accordance with NFPA 31.
505.4 Indirect-Fired Water Heaters. Indirect-fired water heaters shall be in accordance with the applicable sections of the ASME Boiler and Pressure Vessel Code or shall comply with one of the other applicable standards shown in Table 501.1(1). Each water heater shall bear a label in accordance with ASME requirements, or an approved testing agency, certifying and attesting that such an appliance has been tested, inspected and meets the requirements of the applicable standards or code. 505.4.1 Single-Wall Heat Exchanger. An indirectfired water heater that incorporates a single-wall heat exchanger shall be in accordance with the following requirements:
(1) The heat transfer medium shall be either potable water or contain fluids recognized as safe by the Food and Drug Administration (FDA) as food grade.
(2) Bear a label with the word “Caution,” followed by the following statements:
(a) The heat-transfer medium shall be potable water or other nontoxic fluid recognized as safe by the FDA.
(b) The maximum operating pressure of the heat exchanger shall not exceed the maximum operating pressure of the potable water supply.
(3) The word “Caution” and the statements in letters shall have an uppercase height of not less than 0.120 of an inch (3.048 mm). The vertical spacing between lines of type shall be not less than 0.046 of an inch (1.168 mm). Lowercase letters shall be compatible with the uppercase letter size specification.
506.0 Air for Combustion and Ventilation.
506.1 General. Air for combustion, ventilation, and dilution of flue gases for appliances installed in buildings shall be obtained by application of one of the methods covered in Section 506.2 through Section 506.7.3. Where the requirements of Section 506.2 are not met, outdoor air shall be introduced in accordance with methods covered in Section 506.4 through Section 506.7.3.
Exception: This provision shall not apply to direct vent appliances. {NFPA 54:9.3.1.1} 506.1.1 Other Types of Appliances. Appliances of other than natural draft design, appliances not designated as Category I vented appliances, and appliances equipped with power burners shall be provided with combustion, ventilation, and dilution air in accordance with the appliance manufacturer’s instructions. [NFPA 54:9.3.1.2]
CPC § 507.2 High relevance — show source text
2_
507.2|||X|X|X|||X||||||||||||||||| |Adopting Agency
Adopt Entire Chapter
Adopt Entire Chapter as
amended (amended
sections listed below)
Adopt only those sections
that are listed below
Chapter/Section
501.2
507.2|||||||||||||||||||||X|||| |Adopting Agency
Adopt Entire Chapter
Adopt Entire Chapter as
amended (amended
sections listed below)
Adopt only those sections
that are listed below
Chapter/Section
501.2
507.2||||||||||||||||||||||||| |Adopting Agency
Adopt Entire Chapter
Adopt Entire Chapter as
amended (amended
sections listed below)
Adopt only those sections
that are listed below
Chapter/Section
501.2
507.2|||||||||||||||||||||X|||| |Adopting Agency
Adopt Entire Chapter
Adopt Entire Chapter as
amended (amended
sections listed below)
Adopt only those sections
that are listed below
Chapter/Section
501.2
507.2|||X|X|X|||X|||||||||||||||||This state agency does not adopt sections identified with the following symbol: The Office of the State Fire Marshal’s adoption of this chapter or individual sections is applicable to structures regulated by other state agencies pursuant to Section 1.11.0.
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CHAPTER 5
WATER HEATERS
501.0 General.
501.1 Applicability. The regulations of this chapter shall govern the construction, location, and installation of fuel-burning and other types of water heaters heating potable water, together with chimneys, vents, and their connectors. The minimum capacity for storage water heaters shall be in accordance with the first-hour rating listed in Table 501.1(2). A list of accepted water heater appliance standards is referenced in Table 501.1(1). Listed appliances shall be installed in accordance with the manufacturer’s installation instructions. Unlisted water heaters shall be permitted in accordance with Section 504.3.2.
Water heaters shall be installed in accordance with the
manufacturer’s installation instructions. The final installation shall be approved by the Authority Having Jurisdiction.
TABLE 501.1(1)
WATER HEATERS
CPC § 54-2018 High relevance — show source text
Clearance for unlisted water heaters shall be not less than 12 inches (305 mm) on all sides. Combustible floors under unlisted water heaters shall be protected in an approved manner. {NFPA 54-2018:10.27.2.2} 504.4 Pressure-Limiting Devices. A water heater installation shall be provided with overpressure protection using an approved, listed device installed in accordance with the terms of its listing and the manufacturer’s installation instructions. Pressure relief devices shall have a pressure setting greater than the water service pressure and not exceed 150 psi (1034 kPa) as required in Section 608.4. 504.5 Temperature Limiting Devices. A water heater installation or a hot water storage vessel installation shall be provided with overtemperature protection by means of an approved, listed device installed in accordance with the terms of its listing and the manufacturer’s installation instructions. {NFPA 54:10.26.5} 504.6 Temperature, Pressure, and Vacuum Relief Devices. Temperature, pressure, and vacuum relief devices or combinations thereof, and automatic gas shutoff devices shall be installed in accordance with the terms of their listings and the manufacturer’s installation instructions. A shutoff valve shall not be placed between the relief valve and the water heater or on discharge pipes between such valves and the atmosphere. The hourly British thermal units (Btu) (kW•h) discharge capacity or the rated steam relief capacity of the device shall be not less than the input rating of the water heater. {NFPA 54:10.26.6} Discharge piping shall be installed in accordance with Section 608.5.
504.7 Lead Content. Water heaters shall comply with the lead content requirements of Section 604.2.
505.0 Oil-Burning and Other Water Heaters. 505.1 Water Heaters. Water heaters deriving heat from fuels or types of energy other than gas shall comply with the standards referenced in Table 501.1(1), Section 505.3, or Section 505.4. Vents or chimneys for such appliances shall be of approved types. An adequate supply of air for combustion and for adequate ventilation of heater rooms or compartments shall be provided. Each such appliance shall be installed in a
location approved by the Authority Having Jurisdiction and local and state fire-prevention agencies. 505.2 Safety Devices. Storage-type water heaters and hot water boilers deriving heat from fuels or types of energy other than gas, shall be provided with, in addition to the primary temperature controls, an over-temperature safety protection device that complies with and is installed in accordance with nationally recognized applicable standards for such devices and a combination temperature and pressure-relief valve.
505.3 Oil-Fired Water Heaters. Oil-fired water heaters
shall be installed in accordance with NFPA 31.
505.4 Indirect-Fired Water Heaters. Indirect-fired water heaters shall be in accordance with the applicable sections of the ASME Boiler and Pressure Vessel Code or shall comply with one of the other applicable standards shown in Table 501.1(1). Each water heater shall bear a label in accordance with ASME requirements, or an approved testing agency, certifying and attesting that such an appliance has been tested, inspected and meets the requirements of the applicable standards or code. 505.4.1 Single-Wall Heat Exchanger. An indirectfired water heater that incorporates a single-wall heat exchanger shall be in accordance with the following requirements:
CPC § 29.3 High relevance — show source text
Exceptions:
(1) Water heaters installed in individual dwelling units.
(2) Individual gas water heaters with input capacity not greater than 100 000 Btu/h (29.3 kW). [ASHRAE 90.1:7.5.3] L 503.4.4 Heat Recovery for Service Water Heating. Condenser heat recovery systems shall be installed for heating or preheating of service hot water provided all of the following are true:
(1) The facility operates 24 hours a day.
(2) The total installed heat rejection capacity of the water-cooled systems exceeds 6 000 000 Btu/h (1758 kW) of heat rejection.
(3) The design service water-heating load exceeds 1 000 000 Btu/h (293 kW). [ASHRAE 90.1:6.5.6.2.1]
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APPENDIX L
L 503.4.5 Capacity. The required heat recovery system shall have the capacity to provide the smaller of:
(1) Sixty percent of the peak heat-rejection load at design conditions or
(2) Preheat of the peak service hot-water draw to 85°F (29°C).
Exceptions:
(1) Facilities that employ condenser heat recovery for space heating with a heat recovery design exceeding 30 percent of the peak water-cooled condenser load at design conditions.
(2) Facilities that provide 60 percent of their service water heating from onsite renewable energy or siterecovered energy or from other sources. [ASHRAE 90.1:6.5.6.2.2] L 503.5 Submittals. The Authority Having Jurisdiction shall require submittal of compliance documentation and supplemental information in accordance with Section 104.3.1 of this code.
L 504.0 Solar Water Heating Systems.
L 504.1 General. The erection, installation, alteration, addition to, use or maintenance of solar water heating systems shall be in accordance with this section and the Uniform Solar Energy and Hydronics Code.
L 504.2 Annual Inspection and Maintenance. Solar energy systems that utilize a heat transfer fluid shall annually be inspected unless inspections are required on a more frequent basis by the solar energy system manufacturer.
L 505.0 Hard Water.
L 505.1 Softening and Treatment. Where water has a hardness equal to or exceeding 10 gr/gal (171 mg/L) measured as total calcium carbonate equivalents, the water supply line to water heating equipment and the circuit of boilers shall be softened or treated to prevent accumulation of limescale and consequent reduction in energy efficiency.
L 506.0 Drain Water Heat Exchangers. L 506.1 General. Drain water heat exchangers shall comply with IAPMO PS 92. The heat exchanger shall be accessible.
CPC § 101-2017 High relevance — show source text
1| |PDI|PDI|PDI|PDI| |PDI G-101-2017|Testing and Rating Procedure for Hydro Mechanical Grease
Interceptors with Appendix of Installation and Maintenance|DWV Components|Table 1009.1, 1014.1| |PDI G-102-2009|Testing and Certification for Grease Interceptors with FOG
Sensing and Alarm Devices|Certification|Table 1009.1, 1014.1| |PDI-WH 201-2017|Water Hammer Arresters|Water Supply
Components|609.11| |UL
|UL
|UL
|UL
| |UL 103-2010|Factory-Built Chimneys for Residential Type and Building
Heating Appliances (with revisions through September 24,
2021)|Fuel Gas, Appliances|509.5.1, 509.5.1.1| |UL 174-2004|Household Electric Storage Tank Water Heaters (with revisions
through December 16, 2021)|Appliances|Table 501.1(1)| |UL 263-2011|Fire Tests of Building Construction and Materials (with revisions
through August 5, 2021)|Miscellaneous|1404.3, 1405.3|350 2025 CALIFORNIA PLUMBING CODE
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REFERENCED STANDARDS
TABLE 1701.1 (continued) REFERENCED STANDARDS
STANDARD NUMBER STANDARD TITLE APPLICATION REFERENCED
SECTIONUL 378-2006 Draft Equipment (with revisions through September 17, 2013) Fuel Gas, Appliances 509.3.3, 509.13,
509.14.1UL 399-2017 Drinking Water Coolers (with revisions through July 31, 2020) Fixtures 415.1 UL 430-2015 Waste Disposers (with revisions through September 14, 2021) Appliances 419.1 UL 441-2016 Gas Vents (with revisions through August 28, 2019) Fuel Gas, Vents 509.1 UL 467-2013 Grounding and Bonding Equipment (with revisions through
June 7, 2017)Miscellaneous 1211.2.5 UL 499-2014 Electric Heating Appliances (with revisions through October
22, 2021)Appliances Table 501.1(1) UL 641-2010 Type L Low-Temperature Venting Systems (with revisions
through April 23, 2018)Fuel Gas 509.1 UL 723-2018 Test for Surface Burning Characteristics of Building Materials Miscellaneous 701.2(2), 903.1(2),
1101.4UL 732-2018 Oil-Fired Storage Tank Water Heaters (with revisions through
August 9, 2018)Fuel Gas, Appliances Table 501.1(1) UL 749-2018 Household Dishwashers Appliances 414. CPC § 25.4 High relevance — show source text
8
10
15
20
30
50
100|NA
NA
606
682
742
816
879
NA|458
501
538
611
668
747
831
NA|188
218
236
283
325
381
461
499|NA
724
776
874
955
1062
1165
NA|582
636
686
781
858
969
1089
NA|246
278
302
365
419
496
606
669|1041
1144
1226
1374
1513
1702
1905
2053|853
937
1010
1156
1286
1473
1692
1921|NA
408
454
546
648
749
922
1058|For SI units: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1000 British thermal units per hour = 0.293 kW, 1 square inch = 0.000645 m [2]
- NA: Not applicable.
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WATER HEATERS
TABLE 510.2(4) MASONRY CHIMNEY [NFPA 54: TABLE 13.2(d)]*
Col1 Col2 Col3 Col4 Col5 NUMBER OF APPLIANCES: Col7 Col8 Col9 Col10 Col11 TWO OR MORE Col13 Col14 Col15 Col16 Col17 APPLIANCE TYPE: APPLIANCE TYPE: APPLIANCE TYPE: APPLIANCE TYPE: APPLIANCE TYPE: APPLIANCE TYPE: ** CATEGORY I** ** CATEGORY I** ** CATEGORY I** ** CATEGORY I** ** CATEGORY I** ** CATEGORY I** APPLIANCE VENT CONNECTION: APPLIANCE VENT CONNECTION: APPLIANCE VENT CONNECTION: APPLIANCE VENT CONNECTION: APPLIANCE VENT CONNECTION: APPLIANCE VENT CONNECTION: ** SINGLE-WALL METAL CONNECTOR** ** SINGLE-WALL METAL CONNECTOR** ** SINGLE-WALL METAL CONNECTOR** ** SINGLE-WALL METAL CONNECTOR** ** SINGLE-WALL METAL CONNECTOR** ** SINGLE-WALL METAL CONNECTOR** VENT CONNECTOR CAPACITY VENT CONNECTOR CAPACITY VENT CONNECTOR CAPACITY VENT CONNECTOR CAPACITY VENT CONNECTOR CAPACITY VENT CONNECTOR CAPACITY VENT CONNECTOR CAPACITY VENT CONNECTOR CAPACITY VENT CONNECTOR CAPACITY VENT CONNECTOR CAPACITY VENT CONNECTOR CAPACITY VENT CONNECTOR CAPACITY VENT CONNECTOR CAPACITY **VENT CPC § 25.4 High relevance — show source text
(square inches)| ||63|63|63|78|78|78|113|113|113| ||COMBINED APPLIANCE INPUT RATING IN THOUSANDS OF BTU PER HOUR|COMBINED APPLIANCE INPUT RATING IN THOUSANDS OF BTU PER HOUR|COMBINED APPLIANCE INPUT RATING IN THOUSANDS OF BTU PER HOUR|COMBINED APPLIANCE INPUT RATING IN THOUSANDS OF BTU PER HOUR|COMBINED APPLIANCE INPUT RATING IN THOUSANDS OF BTU PER HOUR|COMBINED APPLIANCE INPUT RATING IN THOUSANDS OF BTU PER HOUR|COMBINED APPLIANCE INPUT RATING IN THOUSANDS OF BTU PER HOUR|COMBINED APPLIANCE INPUT RATING IN THOUSANDS OF BTU PER HOUR|COMBINED APPLIANCE INPUT RATING IN THOUSANDS OF BTU PER HOUR| |VENT
HEIGHT
H
(feet)|FAN
+FAN**|FAN
+NAT|NAT
+NAT|FAN
+FAN|FAN
+NAT|NAT
+NAT|FAN
+FAN|FAN
+NAT|NAT
+NAT| |6
8
10
15
20
30
50
100|NA
NA
606
682
742
816
879
NA|458
501
538
611
668
747
831
NA|188
218
236
283
325
381
461
499|NA
724
776
874
955
1062
1165
NA|582
636
686
781
858
969
1089
NA|246
278
302
365
419
496
606
669|1041
1144
1226
1374
1513
1702
1905
2053|853
937
1010
1156
1286
1473
1692
1921|NA
408
454
546
648
749
922
1058|For SI units: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1000 British thermal units per hour = 0.293 kW, 1 square inch = 0.000645 m [2]
- NA: Not applicable.
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WATER HEATERS
TABLE 510.2(4) MASONRY CHIMNEY [NFPA 54: TABLE 13.2(d)]*
CPC § 25.4 High relevance — show source text
351
342
324
310
295
264
NA
|NA
NA
NA
NA
NA
NA
NA
NA
|100
98
125
153
188
224
301
NA
|659
563
551
532
511
487
448
NA
|395
373
366
354
343
NA
NA
NA
|131
125
156
191
230
270
355
540
|991
828
813
789
764
739
685
584|555
508
501
486
473
458
NA
NA|For SI units: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1000 British thermal units per hour = 0.293 kW, 1 square inch = 0.000645 m [2]
- NA: Not applicable.
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WATER HEATERS
TABLE 510.1.2(2) TYPE B DOUBLE-WALL GAS VENT [NFPA 54: TABLE 13.1(b)] (continued)*
Col1 Col2 Col3 Col4 NUMBER OF APPLIANCES: Col6 Col7 Col8 Col9 SINGLE Col11 Col12 Col13 Col14 APPLIANCE TYPE: APPLIANCE TYPE: APPLIANCE TYPE: APPLIANCE TYPE: APPLIANCE TYPE: ** CATEGORY I** ** CATEGORY I** ** CATEGORY I** ** CATEGORY I** ** CATEGORY I** APPLIANCE VENT CONNECTION: APPLIANCE VENT CONNECTION: APPLIANCE VENT CONNECTION: APPLIANCE VENT CONNECTION: APPLIANCE VENT CONNECTION: ** SINGLE-WALL METAL CONNECTOR** ** SINGLE-WALL METAL CONNECTOR** ** CPC § 6.1507 High relevance — show source text
LIFT = Entering Condenser Water Temperature (°F) – Leaving Chilled Water Temperature (°F)
2. Condenser DT = Leaving Condenser Water Temperature (°F) – Entering Condenser Water Temperature (°F)
Kadj = 6.1507 – 0.30244(×) + 0.0062692(×)2 – 0.000045595(×)3
where× = Condenser DT + LIFT
COPadj = Kadj * COPstd|1. LIFT = Entering Condenser Water Temperature (°F) – Leaving Chilled Water Temperature (°F)
2. Condenser DT = Leaving Condenser Water Temperature (°F) – Entering Condenser Water Temperature (°F)
Kadj = 6.1507 – 0.30244(×) + 0.0062692(×)2 – 0.000045595(×)3
where× = Condenser DT + LIFT
COPadj = Kadj * COPstd|1. LIFT = Entering Condenser Water Temperature (°F) – Leaving Chilled Water Temperature (°F)
2. Condenser DT = Leaving Condenser Water Temperature (°F) – Entering Condenser Water Temperature (°F)
Kadj = 6.1507 – 0.30244(×) + 0.0062692(×)2 – 0.000045595(×)3
where× = Condenser DT + LIFT
COPadj = Kadj * COPstd|1. LIFT = Entering Condenser Water Temperature (°F) – Leaving Chilled Water Temperature (°F)
2. Condenser DT = Leaving Condenser Water Temperature (°F) – Entering Condenser Water Temperature (°F)
Kadj = 6.1507 – 0.30244(×) + 0.0062692(×)2 – 0.000045595(×)3
where× = Condenser DT + LIFT
COPadj = Kadj * COPstd|1. LIFT = Entering Condenser Water Temperature (°F) – Leaving Chilled Water Temperature (°F)
2. Condenser DT = Leaving Condenser Water Temperature (°F) – Entering Condenser Water Temperature (°F)
Kadj = 6.1507 – 0.30244(×) + 0.0062692(×)2 – 0.000045595(×)3
where× = Condenser DT + LIFT
COPadj = Kadj * COPstd|1. LIFT = Entering Condenser Water Temperature (°F) – Leaving Chilled Water Temperature (°F)
2. Condenser DT = Leaving Condenser Water Temperature (°F) – Entering Condenser Water Temperature (°F)
Kadj = 6.1507 – 0.30244(×) + 0.0062692(×)2 – 0.000045595(×)3
where× = Condenser DT + LIFT
COPadj = Kadj * COPstd|A6.207.1.2 Controls for heat pumps with supplementary electric resistance heaters. Heat pumps with supplementary electric resistance heaters shall have controls:
A6.207.1.2.1 That prevent supplementary heater operation when the heating load can be met by the heat pump alone; and
CPC § 25.4 High relevance — show source text
inches)|INTERNAL AREA OF CHIMNEY (square inches)|INTERNAL AREA OF CHIMNEY (square inches)|INTERNAL AREA OF CHIMNEY (square inches)|INTERNAL AREA OF CHIMNEY (square inches)|INTERNAL AREA OF CHIMNEY (square inches)|INTERNAL AREA OF CHIMNEY (square inches)| |VENT HEIGHT
H
(feet)**|12|19|28|38|50|63|78|113| |6
8
10
15
20
30
50
100|74
80
84
NA
NA
NA
NA
NA|119
130
138
152
NA
NA
NA
NA|178
193
207
233
250
NA
NA
NA|257
279
299
334
368
404
NA
NA|351
384
409
467
508
564
NA
NA|458
501
538
611
668
747
831
NA|582
636
686
781
858
969
1089
NA|853
937
1010
1156
1286
1473
1692
1921|For SI units: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1000 British thermal units per hour = 0.293 kW, 1 square inch = 0.000645 m [2]
- NA: Not applicable.
2025 CALIFORNIA PLUMBING CODE 133
), Copyright © 2025 IAPMO, and may not be used for any other purpose or distributed to any other persons or parties.
WATER HEATERS
TABLE 510.2(9) EXTERIOR MASONRY CHIMNEY [NFPA 54: TABLE 13.2(i)]1, Col2 Col3 Col4 , 2 Col6 Col7 Col8 Col9 NUMBER OF APPLIANCES: NUMBER OF APPLIANCES: ** TWO OR MORE** ** TWO OR MORE** ** TWO OR MORE** APPLIANCE TYPE: APPLIANCE TYPE: ** FAN + NAT** ** FAN + NAT** ** FAN + NAT** APPLIANCE VENT CONNECTION: APPLIANCE VENT CONNECTION: ** TYPE B DOUBLE-WALL CONNECTOR** ** TYPE B DOUBLE-WALL CONNECTOR** ** TYPE B DOUBLE-WALL CONNECTOR** MINIMUM ALLOWABLE INPUT RATING OF SPACE-HEATING APPLIANCE IN THOUSANDS OF BTU PER HOUR MINIMUM ALLOWABLE INPUT RATING OF SPACE-HEATING APPLIANCE IN THOUSANDS OF BTU PER HOUR MINIMUM ALLOWABLE INPUT RATING OF SPACE-HEATING APPLIANCE IN THOUSANDS OF BTU PER HOUR MINIMUM ALLOWABLE INPUT RATING OF SPACE-HEATING APPLIANCE IN THOUSANDS OF BTU PER HOUR **MINIMUM ALLOWABLE INPUT RATING OF SPACE-HEATING CPC § 778-2016 Medium relevance — show source text
1| |UL 778-2016|Motor-Operated Water Pumps (with revisions throughJune
29, 2021)|Appliances|1101.14| |UL 921-2020|Commercial Dishwashers|Appliances|414.1| |UL 959-2010|Medium Heat Appliance Factory-Built Chimneys (with revisions
through August 28, 2019)|Fuel Gas, Appliances|509.5.1| |UL 1453-2016|Electric Booster and Commercial Storage Tank Water Heaters
(with revisions through May 18, 2018)|Appliances|Table 501.1(1)| |UL 1479-2015|Fire Tests of Penetration Firestops (with revisions through May
18, 2021)|Miscellaneous|1404.3, 1405.3| |UL 1738-2010|Venting Systems for Gas-Burning Appliances, Categories II,
III, and IV (with revisions through August 26, 2021)|Fuel Gas, Appliances|509.4.1, 509.4.2,
509.4.3| |UL 1777-2015|Chimney Liners (with revisions through April 11, 2019)|Chimney Liners|509.5.3(2)| |UL 2523-2009|Solid Fuel-Fired Hydronic Heating Appliances, Water Heaters,
and Boilers (with revisions through March 16, 2018)|Fuel Gas, Appliances|Table 501.1(1)| |UL 2561-2016|1400 Degree Fahrenheit Factory-Built Chimneys (with revisions
through April 19, 2018)|Fuel Gas, Appli-
ances|509.5.1| |WSC|WSC|WSC|WSC| |ASSE 1099-2021/WSC PST
2000-2021|Pressurized Water Storage Tanks|Valves|607.2|2025 CALIFORNIA PLUMBING CODE 351
), Copyright © 2025 IAPMO, and may not be used for any other purpose or distributed to any other persons or parties.
REFERENCED STANDARDS
1701.2 Standards, Publications, Practices, and Guides. The standards, publications, practices, and guides listed in Table 1701.2 are not referenced in other sections of
this code. The application of the referenced standards, publi
cations, practices, and guides shall be as specified in Section 301.2.2. The promulgating agency acronyms are found at the end of the tables.
TABLE 1701.2
|Col1|STANDARDS, PUBLICATIONS, PRACTICES,
Frequently asked questions
Do all water heaters have to be "listed" to a standard in Table 501.1(1)?
No — the code prefers listed appliances and requires installation per the manufacturer’s instructions, but unlisted water heaters are permitted only under the conditions and process in Section 504.3.2, which is referenced in § 501.1.
Which standard applies for a gas-fired heater rated at 60,000 Btu/h?
A gas‑fired storage heater with input ≤ 75,000 Btu/h must meet CSA/ANSI Z21.10.1 / CSA 4.1 per Table 501.1(1) and § 501.1.
I have an oil-fired heater—what standard or code applies?
Oil‑fired water heaters are listed in Table 501.1(1) (UL 732) and § 505.3 requires installation in accordance with NFPA 31. Verify both the listing and the NFPA requirements.
Where can I find mandatory energy requirements for a new water‑heating system?
See § 501.2, which directs you to relevant California Energy Code sections (for mandatory requirements and additional residential provisions).
If my unit is dual-purpose (space + water heating), what must I do?
Dual‑purpose water heaters must be installed in accordance with the CPC and the manufacturer’s instructions as stated in § 501.1 and the note in Table 501.1(1).
More in California Plumbing Code
- Administration
- Definitions
- General Regulations
- Plumbing Fixtures and Fixture Fittings
- Water Heaters
- Water Supply and Distribution
- Sanitary Drainage (Drain, Waste, and Vent)
- Indirect Wastes
- Vents
- Traps and Interceptors
- Storm Drainage
- Fuel Gas Piping
- Health Care Facilities — Medical Gas and Medical Vacuum Systems
- Alternate Water Sources and Nonpotable Rainwater Catchment Systems
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